<!--
{
  "availability" : [
    "iOS: 9.0.0 -",
    "iPadOS: 9.0.0 -",
    "macCatalyst: 13.1.0 -",
    "macOS: 10.11.0 -",
    "tvOS: 9.0.0 -",
    "visionOS: 1.0.0 -"
  ],
  "documentType" : "symbol",
  "framework" : "ModelIO",
  "identifier" : "/documentation/ModelIO/MDLMaterialProperty/semantic",
  "metadataVersion" : "0.1.0",
  "role" : "Instance Property",
  "symbol" : {
    "kind" : "Instance Property",
    "modules" : [
      "Model I/O"
    ],
    "preciseIdentifier" : "c:objc(cs)MDLMaterialProperty(py)semantic"
  },
  "title" : "semantic"
}
-->

# semantic

The semantic meaning for the material property’s value.

```
var semantic: MDLMaterialSemantic { get set }
```

## Discussion

A material semantic determines how the material property’s value should be interpreted to produce a specific surface appearance in rendering. For example, the [`MDLMaterialSemantic.baseColor`](/documentation/ModelIO/MDLMaterialSemantic/baseColor) semantic defines the default color of each pixel on a rendered surface before shading effects are applied.

When Model I/O  loads materials from an [`MDLAsset`](/documentation/ModelIO/MDLAsset) object, it automatically selects the appropriate standard semantics for the surface rendering descriptions in the asset file.

---

Copyright &copy; 2026 Apple Inc. All rights reserved. | [Terms of Use](https://www.apple.com/legal/internet-services/terms/site.html) | [Privacy Policy](https://www.apple.com/privacy/privacy-policy)